Preheat oven to 400°. Line a large rimmed baking sheet with foil and mist with cooking spray.

In a medium mixing bowl, combine turkey, garlic, egg white, onion, bell peppers, Italian seasoning, salt and pepper. Gently mix until combined. Using a spoon or small scooper, form into bite size balls, about scant Tbsp each, making 24 meatballs, place on sheet. (Make ahead: prepare meatballs up to one day in advance, wrap tray in plastic wrap and refrigerate.)

Transfer to oven and bake for 10 minutes. Remove from oven and flip over. Bake for 10 more minutes or until cooked through. Remove from oven, using a fork or tongs, transfer each meatball to a serving dish.

Heat the marinara sauce, pour over the meatballs. Serve with a serving spoon or have toothpicks next to the dish.